A method for depositing a liner dielectric on a semiconductor substrate provides for sufficient adhesion of low dielectric constant spin-on materials among metal layers in sub-micron processes. In an example embodiment, a method for adhering MSQ provides for a liner oxide on an aluminum alloy layer on a semiconductor substrate. First, the substrate is placed into a PECVD environment. A gas mixture of trimethylsilane and N.sub.2 O is introduced into the PECVD environment at a trimethylsilane-to-N.sub.2 O ratio of about 1:20 to 1:30. The gas mixture is reacted to deposit an oxide liner of a predetermined thickness. Adjusting the gas mixture trimethylsilane-to-N.sub.2 O ratio to about 1:3 to 1:7 over the course of about 5 to 20 seconds, and sustaining the reaction thereof, deposits a methyl doped oxide.
Legal claims defining the scope of protection, as filed with the USPTO.
1. On a semiconductor substrate, a method of adhering a spin-on dielectric on a metal layer comprising: depositing a first predetermined thickness of a liner dielectric on the metal layer, the liner dielectric having a chemical affinity to the metal layer; forming a transition layer of a second predetermined thickness on the liner dielectric, the transition layer having less chemical affinity to the metal layer and increasing chemical affinity to the spin-on dielectric as the thickness of the transition layer increases; and depositing a third predetermined thickness of liner dielectric on the transition layer, the liner dielectric having a chemical affinity to the spin-on dielectric.
2. The method of claim 1 wherein the spin-on dielectric includes at least one of the following: methyl silsesquioxane, hydrogen silsesquioxane.
3. The method of claim 2 wherein the first predetermined thickness of liner dielectric includes silicon dioxide, silicon-rich oxide, and Si.sub.x O.sub.y.
4. The method of claim 3 wherein the transition layer comprises a region of silicon dioxide transitioning to a region of methyl doped oxide.
5. The method of claim 1 wherein, the liner dielectric is deposited by one of the following: chemical vapor deposition (CVD) and plasma-enhanced chemical vapor deposition (PECVD); and wherein, the transition layer is formed by one of the following: chemical vapor deposition (CVD) and plasma-enhanced chemical vapor deposition (PECVD).
6. The method of claim 5 wherein the transition layer comprises a methyl doped oxide film formed in a PECVD environment using precursor gases selected from at least one of the following: trimethylsilane, tetramethylsilane.
7. The method of claim 6 wherein the precursor gas is blended with nitrogen oxide (N.sub.2 O) in a predetermined ratio to yield silicon dioxide transitioning to methyl doped oxide.
8. The method of claim 7 wherein the transition layer is deposited with a thickness in the range of about 100 .ANG. to 2000 .ANG.; and wherein, the SiO.sub.2 thickness is in the range of about 50 .ANG. to about 100 .ANG.; and wherein the methyl doped oxide thickness is in the range of about 50 .ANG. to about 1000 .ANG..
9. A method for adhering a silsesquioxane compound, providing a liner dielectric on an aluminum alloy metal layer on a semiconductor substrate, the method comprising: placing the substrate in a CVD environment; introducing a gas mixture into the CVD environment, wherein the gas mixture comprises a precursor gas and N.sub.2 O at a defined precursor gas-to-N.sub.2 O ratio; and reacting the gas mixture to deposit the liner dielectric of a predetermined thickness.
10. The method of claim 9 wherein reacting the gas mixture comprises, adjusting the precursor gas-to-N.sub.2 O ratio so that silicon dioxide is deposited on the aluminum alloy metal layer at a first predetermined thickness; and re-adjusting the precursor gas-to-N.sub.2 O ratio so that methyl doped oxide is deposited on the silicon dioxide at a second predetermined thickness.
11. The method of claim 10 wherein the re-adjusting the precursor gas-to-N.sub.2 O ratio transitions the liner dielectric from a region of silicon dioxide to a region of methyl doped oxide.
12. The method of claim 9 wherein the precursor gas includes at least one of the following: trimethylsilane, tetramethylsilane.
13. A method for adhering a silsesquioxane compound providing a liner oxide on an aluminum alloy metal layer on a semiconductor substrate, the method comprising: placing the substrate in a PECVD environment; introducing a gas mixture into the PECVD environment, wherein the gas mixture comprises a precursor gas and N.sub.2 O at a precursor gas-to-N.sub.2 O first ratio of about 1:20 to 1:30; reacting the gas mixture to deposit an oxide liner of a thickness in the range of about 100 .ANG. to 1000 .ANG.; and adjusting the gas mixture and sustaining the reaction thereof of the precursor gas and N.sub.2 O at a precursor gas-to-N.sub.2 O second ratio of about 1:3 to about 1:7 to deposit a methyl doped oxide liner of a thickness in the range of about 100 .ANG. to 1000 .ANG..
14. The method of claim 13 wherein the adjusting of the gas mixture from the first precursor gas-to-N.sub.2 O ratio to the second precursor gas-to-N.sub.2 O ratio takes about 3 to 30 seconds.
15. The method of claim 13 wherein the precursor gas includes at least one of the following: trimethylsilane, tetramethylsilane.
Cooperative Patent Classification codes for this invention. Click any code to explore related patents in that topic.
August 18, 2000
October 16, 2001
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